If you're looking for something to buy, check with your child's teacher. When they get Scholastic book order forms, many of them get the Software Edition. There are many good products there and so many of them as low as $14.95. We don't send them out much in our school, maybe two or three times a year (we're Title I and most parents can't afford it). For example, Math Munchers is a really good one for math. Just an FYI - I do not work for Scholastic / Troll, but they really are a good place to start!

Pbs.org has tons of activities that go along with their shows. Check out between the lions. I don't know the reading level you need but you could try starfall.com
happychild.org has some interesting stuff too but not games.
My sister loved reader rabbit.
If you want to help him with reading comprehension, the card games like Yugi-oh! have instructions on each card. Players have to understand what they have read to play. Lots of kids his age are playing those games.

Not a PTO topic, but I could use some referrals...

I'm looking for educational software to supplement language arts at the 4th/5th grade level.

My son needs some supplemental help with punctuation, grammer, maybe a bit of reading comprehension. He loves the computer and I think will respond better to an online program than worksheets. He also tends to respond better to online assessments and testing than when we try to help him. The computer tells him he's wrong >>> try again. Mom or Dad tell him he's wrong >>> moan, groan, delay, and procrastinate.

Does anyone have any leads for software they've tried themselves or heard good things about?